1. Field of the Invention
The present invention relates to shoes. In particular, the present invention relates to shoes having an outsole with a spike.
2. Description of the Related Art
When a golfer takes a shot from a tee box or fairway, the golfer swings on grass. When the golfer takes a shot from a bunker, the golfer swings on sand. If the golfer""s foot slips on the ground during swinging, the golfer will make an erroneous shot. While the golfer goes round, the golfer walks on the fairway and the rough, which rises and falls. When the golfer""s foot slips during walking, the golfer has an increased burden on the feet. To prevent from slipping during swinging and walking, the golfer wears golf shoes (so-called spikes) having a plurality of spikes formed on the bottom surface thereof. Each spike has a single pin formed at the center of the lower surface of the disk-shaped flange thereof and is made of a metal or ceramic material. The spike cuts into the grass, thus preventing the golfer""s foot from slipping thereon.
Frequently, the golfer is required to walk not only on the grass and the sand, but also on a hard ground paved with asphalt or concrete, for example, a path located between the putting green and the tee box of a subsequent hole, a club house, and the like. The spike does not cut into the hard ground, thus being incapable of sufficiently preventing the golfer""s foot from slipping thereon. Further, the spikes give the golfer a feeling that pressure is applied upward to the golfer""s feet. Thus, the spikes are not comfortable to wear. Furthermore, the spike may injure the lawn (lawn on putting green in particular).
To solve the above-described disadvantages, a soft-type spike has been proposed and is coming into popular use. The soft-type spike is formed of a molded elastic material such as synthetic resin. The area of the part of the soft-type spike that contacts the ground is increased by forming many projections thereon and shaping it trapezoidally in its vertical sectional configuration. An example of a soft-type spike is disclosed in Japanese Registered Utility Model Publication No. 3027022. However, the soft-type spike is incapable of sufficiently preventing the golfer""s foot from slipping on hard ground. Furthermore, there is still room for improvement of the soft-type spike to prevent slipping on wet ground in particular.
A golf shoe not having a spike but having an elastic projection formed on the bottom surface thereof is disclosed in Japanese Patent Publication 6-22482. The elastic projection prevents the golfer""s foot from slipping on hard ground but hardly cuts into the lawn. Therefore, the golf shoes are incapable of sufficiently preventing the golfer""s foot from slipping during swinging.
A golf shoe having a spike and a projection on the surface which contacts the ground is disclosed in Japanese Patent Application Laid-Open No. 11-89605. In the above golf shoes, the spike mainly prevents slipping on, and the projection mainly prevents slipping on hard ground.
However, the golf shoes disclosed in Japanese Patent Application Laid-Open No. 11-89605 are not satisfactory in preventing slipping on both grass and hard ground. The above golf shoes have another problem in that the spike is liable to chip and wear.
The present invention has been made in view of the above-described situation. Thus, it is an object of the present invention to provide shoes preventing a golfer""s foot from easily slipping on the ground and its spike from chipping easily and wearing in a short period of time.
To achieve the object, according to the present invention, there are provided shoes having an outsole including a spike and a projected portion having a ground-contact surface formed thereon. A ground-contact portion of the spike is made of a rubber-molded material whose JIS-C hardness is set to the range from 35 to 95 both inclusive and whose cutting-time elongation is 280% or more; the rubber-molded material contains 30 wt % or more of polybutadiene as a rubber component thereof; and the difference (h1xe2x88x92h2) between a projected height h1 of the spike and a projected height h2 of the projected portion is set to the range from 0 mm to 15 mm both inclusive.
To achieve the object, according to the present invention, there are provided shoes having an outsole including a spike and a projected portion having a ground-contact surface formed thereon. A ground-contact portion of the spike is made of a rubber-molded material whose JIS-C hardness is set to the range from 35 to 95 both inclusive and whose cutting-time elongation is 280% or more; the rubber-molded material contains 30 wt % or more of Polybutadiene as a rubber component thereof; and the difference (h1xe2x88x92h2) between a projected height h1 of the spike and a projected height h2 of the projected portion is set to the range from 0 mm to 15 mm both inclusive.
Further, according to the another invention, there are provided shoes having an outsole including a spike and a projected portion having a ground-contact surface formed thereon,
wherein a ground-contact portion of said spike is made of a rubber-molded material whose JIS-C hardness is set to the range from 35 to 95 both inclusive and whose cutting-time elongation is set to 280% or more; said rubber-molded material contains 30 wt % or more of acrylonitrile-butadiene copolymer as a rubber component thereof; and the difference (h1xe2x88x92h2) between a projected height h1 of said spike and a projected height h2 of said projected portion is set to the range from 0 mm to 15 mm both inclusive.
Accordingly, the shoes prevent slipping on both grass and hard ground. The cutting-time elongation of the rubber-molded material is set to 280% or more. Therefore, chipping of the spike can be suppressed. The rubber-molded material contains 30 wt % or more of polybutadiene or acrylonitrile-butadiene copolymer as a rubber component thereof. Thus, wear of the spike can be suppressed. The difference (h1xe2x88x92h2) between the projected height h1 of the spike and the projected height h2 of the projected portion is set to the range from 1 mm to 15 mm both inclusive. Therefore, it is comfortable for a golfer to wear the shoes and possible to prevent the grass from being injured.
In the case where polybutadiene is used for the spike, preferably, the polybutadiene contains a cis-1,4 linkage at 70% or more of a micro-structure thereof. Thereby, the wear of the spike can be suppressed to a higher extent.
Preferably, the spike is removably mounted on the outsole. Thereby, the spike can be replaced easily when it is worn.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.